Microstructural study of adiabatic shear bands formed in serrated chips during high-speed machining of hardened steel

2009 ◽  
Vol 44 (3) ◽  
pp. 897-902 ◽  
Author(s):  
C. Z. Duan ◽  
Y. J. Cai ◽  
M. J. Wang ◽  
G. H. Li
Keyword(s):  
High Speed ◽  
Shear Bands ◽  
Hardened Steel ◽  
Adiabatic Shear ◽  
High Speed Machining ◽  
Adiabatic Shear Bands ◽  
Microstructural Study ◽  
Serrated Chips

Adiabatic Shear Localization in High Speed Cutting of Hardened Steel

2011 ◽  
Vol 55-57 ◽  
pp. 983-987 ◽  
Author(s):  
Chun Zheng Duan ◽  
Wei Sen Kong ◽  
Zhao Xi Wang ◽  
Min Jie Wang
Keyword(s):  
Shear Band ◽  
High Speed ◽  
Adiabatic Shear Band ◽  
Shear Bands ◽  
Cutting Speed ◽  
Shear Localization ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
High Speed Cutting ◽  
Serrated Chips

The formation and development of adiabatic shear localization in serrated chips have great significance to study of mechanism of high speed cutting. This paper investigates the theory prediction and experimental verification of the critical cutting speed of adiabatic shear localization, distribution of adiabatic shear band in serrated chip and the geometry of adiabatic shear band during high speed cutting of hardened steel. The results indicated that the theoretical prediction of critical cutting speed is consistent with the experimental results.With the increase of cutting speed, the width and spacing of adiabatic shear bands in the serrated chips decrease linearly. There are two types of adiabatic shear bands during the formation and development of adiabatic shear localization, i.e. the deformation shear band and the transformed shear band.

Microscopic Examination of Primary Shear Zone in High Speed Machining of Hardened High Strength Steel

2010 ◽  
Vol 97-101 ◽  
pp. 1887-1890 ◽  
Author(s):  
Chun Zheng Duan ◽  
Min Jie Wang ◽  
Tao Dou
Keyword(s):  
Shear Zone ◽  
High Strength Steel ◽  
High Speed ◽  
Shear Bands ◽  
Cutting Speed ◽  
High Strength ◽  
Optical Microscope ◽  
Adiabatic Shear ◽  
High Speed Machining ◽  
Adiabatic Shear Bands

The microstructure observation and microhardness measurement were performed on the adiabatic shear bands in primary shear zone in the serrated chips formed during high speed machining of two tempering hardness of hardened high strength steel under different cutting speeds by optical microscope, SEM, TEM and microhardness tester. The investigation results show that two types of adiabatic shear bands are formed as cutting speed increases. One is deformed band with heavy elongated microstructures generated under lower cutting speed, another is transformed band with fine grains under higher cutting speed. The increase of the cutting speed little influences on the microhardness in the transformed bands, and the microhardness in deformed band results from strain hardening, whereas transformation hardening leads to very high microhardness in transformed band.

An Investigation into the Microstructure of Adiabatic Shear Banding in AISI 1045 Hardened Steel due to High Speed Machining

2010 ◽  
Vol 154-155 ◽  
pp. 321-324 ◽  
Author(s):  
Chun Zheng Duan ◽  
Liang Chi Zhang ◽  
Hai Yang Yu ◽  
Min Jie Wang
Keyword(s):  
High Speed ◽  
Shear Banding ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
High Speed Machining ◽  
Adiabatic Shear Bands ◽  
Adiabatic Shear Banding ◽  
Aisi 1045 ◽  
Cutting Speeds ◽  
Electronic Microscope

Adiabatic shear banding during high speed machining is important to understand material removal mechanisms. This paper investigates the microstructure of adiabatic shear bands (ASBs) in the serrated chips produced during the high speed machining of AISI 1045 hardened steel. Optical microscope, scanning electronic microscope(SEM) and transmission electronic microscope(TEM) were used to explore the microstructural characteristics. It was found that there are two types of adiabatic shear bands. One is the deformed adiabatic shear band composed of a significantly deformed structure generated in a range of low cutting speeds, and the other is the transformed adiabatic shear band composed of very small equiaxed grains generated under high cutting speeds. The results indicated that the deformed band has a tempered martensite structure that formed through large plastic deformation and the transformed band has experienced a dynamic recrystallization process.

Influence of Cutting Conditions on the Width of Adiabatic Shear Bands: An Investigation Using Finite Element Simulation

2013 ◽  
Vol 820 ◽  
pp. 194-199
Author(s):  
Tao Cui ◽  
Hong Wei Zhao ◽  
Ye Tian ◽  
Chuang Liu
Keyword(s):  
High Speed ◽  
Shear Bands ◽  
Chip Thickness ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
High Speed Cutting ◽  
Model Combining ◽  
Cutting Velocity ◽  
Microstructure Prediction

In this paper, a novel model combining the microstructure prediction model and a modified constitutive model of the Johnson-Cook (JC) model was developed and embedded into FEM software via the user subroutine. The chip formation and microstructure evolution in high speed cutting of Ti-6Al-4V alloy were simulated. The results indicated that dynamic recrystallization mainly happened in adiabatic shear bands (ASBs), where the grain size had a big decline. Then FEM simulations were carried out to investigate the effect of cutting velocity, uncut chip thickness, and the rake angle on the ASBs width of the serrated chips. It can be concluded that the width of ASB increases with the increasing of cutting depth and cutting velocity, and decreases with the increasing of rake angle of the tool.

Some Metallurgical Observations of Adiabatic Shear Phenomenon During High Speed Machining AISI 1045 Hardened Steel

2011 ◽  
Vol 4 (6) ◽  
pp. 2493-2497 ◽  
Author(s):  
Chunzheng Duan ◽  
Haiyang Yu ◽  
Honghua Li ◽  
Minjie Wang
Keyword(s):  
High Speed ◽  
Hardened Steel ◽  
Adiabatic Shear ◽  
High Speed Machining ◽  
Aisi 1045

Microscopic Observation of White Band within Shear Zone of Chip Produced during High Speed Machining of AISI 1045 Hardness Steel

2011 ◽  
Vol 474-476 ◽  
pp. 1292-1295
Author(s):  
Chun Zheng Duan ◽  
Wei Sen Kong ◽  
Zhao Xi Wang ◽  
Min Jie Wang
Keyword(s):  
Deformation Zone ◽  
High Speed ◽  
Chemical Elements ◽  
Adiabatic Shear ◽  
High Speed Machining ◽  
X Ray Diffraction ◽  
Serrated Chip ◽  
White Band ◽  
Aisi 1045 ◽  
Serrated Chips

To study the microstructure of white band is helpful for revealing formation mechanism of serrated chip. This paper investigates the microstructural characteristics of white bandsat primary and second deformation zone within the serrated chips produced during High Speed Machining (HSM) of AISI 1045 hardened steel usingoptical microscope, SEM, TEM, and electron microprobe, X-Ray diffraction. It was found that the white bands within primary and second deformation zone consist of small equiaxed grains which formed due to dynamic recrystallization during adiabatic shear, however, martensitic transformation just only taken place within the white band in second deformation zone. The re-distribution of chemical elements between the composition phases occurred due to the combined effect of adiabatic temperature rise and high speed deformation in formation process of white band. The former is result from adiabatic shear in primary deformation zone during formation of chip, while the latter is caused by the intense shear and friction between tool and chip.

Numerical Simulation of Adiabatic Shear Behavior in High-Speed Machining of Hardened Steel GCr15

2009 ◽  
Vol 69-70 ◽  
pp. 476-479
Author(s):  
Tao Chen ◽  
Xian Li Liu ◽  
G.T. Luo ◽  
Fu Gang Yan ◽  
Dong Kai Jia
Keyword(s):  
Shear Band ◽  
Cutting Force ◽  
High Speed ◽  
Numerical Range ◽  
Adiabatic Shear Band ◽  
Large Strain ◽  
Shear Behavior ◽  
Hardened Steel ◽  
Adiabatic Shear ◽  
High Speed Machining

In this paper, FEM is used to simulate the three stages of catastrophic shear occurrence, expansion and shear band formation when serrated chips are formed under adiabatic shear behavior in high-speed machining of hardened steel GCr15 with PCBN tool. By comparing data of simulation and experiment on chip morphology characters, it is indicated that they are in good accordance. Hereby, the author has analyzed strain and temperature distribution in adiabatic shear band, and dynamic characters of cutting force . The research results show that adiabatic shear band begins from tool tip and extends to workpiece free surface, and it is characterized by large strain and high temperature. In addition, it results from adiabatic shear behavior that cutting force waves regularly in a numerical range.

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